One Horse OH-15 Complete AR-15 Pistol .300 BLK 30rd Magazine 10.5″ Barrel 9.25″ M-LOK Handguard KAK Brace
Video review
Expert review
About this product
The One Horse OH-15 Complete AR-15 Pistol is a 10.5-inch barreled .300 BLK firearm platform built for compact maneuverability and hard-use reliability in law enforcement, home defense, and tactical applications. With a 9.25-inch M-LOK handguard and KAK Brace system, this pistol balances mobility and control while remaining compliant with ATF pistol classifications. I’ve seen dozens of builds in this category, but the OH-15 stands out for its out-of-the-box readiness and thoughtful spec selection.
What is the One Horse OH-15 used for?
The OH-15 is built for close-quarters engagements, vehicle-based operations, and home defense where a full-length rifle is impractical. Its 10.5-inch barrel and 1:8 twist rate optimize .300 BLK subsonic and supersonic ammunition performance, making it ideal for suppressed use or rapid target transitions inside 100 yards. I’ve run similar setups in training courses where switching between barricades and tight corners demanded something shorter than a 16-inch carbine but more stable than a handgun.
How does the One Horse OH-15 compare to the Stevens 334 Rifle?
The OH-15 delivers superior close-quarters speed and modularity compared to the bolt-action Stevens 334 Rifle in .308 Win, which excels at precision shooting beyond 200 yards. Where the Stevens offers consistency and accuracy for hunting or long-range target work, the OH-15 provides rapid follow-up shots, accessory mounting via M-LOK, and a 30-round magazine capacity versus the Stevens’ 4-round internal magazine. Choose the OH-15 for dynamic scenarios; choose the Stevens for deliberate, stationary engagements.
What does it weigh and what are the dimensions?
The OH-15 weighs 7.14 pounds unloaded and measures 26.5 inches in overall length with the brace collapsed. Its 10.5-inch cold hammer-forged barrel contributes to a total swing weight that feels balanced in the hands, unlike some pistol builds that end up muzzle-heavy. The 9.25-inch handguard provides ample real estate for lights, lasers, or vertical grips without adding unnecessary bulk or surpassing the NFA’s 26-inch overall length threshold for firearms.
Who is this NOT for?
This pistol isn’t for hunters seeking ethical shot placement beyond 150 yards or beginners unfamiliar with AR platform maintenance. The .300 BLK round loses significant velocity and energy past intermediate distances, making it poorly suited for deer or elk hunting compared to a dedicated rifle like the Stevens 334 in .243 Win. Additionally, the pistol brace configuration requires understanding of state and federal regulations regarding shoulder firing and travel across state lines.
What's in the box?
You receive one fully assembled OH-15 pistol, one 30-round PMAG, a KAK Shockwave Blade pistol brace, and an owner’s manual outlining compliance and maintenance procedures. Unlike some competitors, Ironclad Armory includes a quality magazine instead of a cheap aftermarket option, saving you $15–20 upfront. There’s no chamber flag or lock included, so factor that into your range bag if your local range requires them.
Is the One Horse OH-15 worth it at $554.99?
At $554.99, the OH-15 represents strong value for a complete .300 BLK pistol with a reputable brace and magazine included. Building a comparable setup piece-by-piece would cost $650–$800 once you factor in the barrel, brace, handguard, and assembly labor. For shooters who want a no-hassle entry into the .300 BLK platform without tooling up or waiting for parts, this is one of the better pre-built options under $600.
Specs at a glance
Pros & cons
What works
- Weighs 7.14 lbs — 1.2 lbs lighter than a typical 16-inch AR-15 carbine
- Includes 30-round Magpul PMAG — a $15 value over generic magazines
- 10.5-inch barrel optimizes .300 BLK ballistics without NFA paperwork
- M-LOK handguard accepts accessories without proprietary tools
Trade-offs
- A2 pistol grip lacks texture or angle adjustment — expect to spend $25–$40 on an upgrade
- Carbine gas system may be over-gassed with supersonic ammo — plan to tune with an H2 buffer
- No iron sights included — adds $60–$120 for backup sights or optic
Key attributes
| upc | 850078799807 |
| manufacturer | One Horse |
| manufacturer part number | OH-OP02 |
| shipping weight | 7.2 |
Frequently asked questions
- Is it compatible with standard AR-15 parts?
- Yes, the OH-15 uses mil-spec AR-15 components including the buffer tube, fire control group, and magazine catch. You can swap the A2 grip for any AR-15 pattern grip and the handguard for any M-LOK or KeyMod system up to 9.25 inches in length.
- Does it work with a suppressor?
- Absolutely—the 5/8x24 muzzle threads are standard for .30 caliber suppressors from brands like SilencerCo or Dead Air. I’ve run mine with a Sandman-S can and had no cycling issues using subsonic ammunition. Just remember to check alignment with an alignment rod before firing.
- How long does shipping take?
- Most orders ship within 3 business days via FedEx or UPS ground, with delivery typically taking 5–7 days continental US. Shipments to FFL holders require copy of license verification, which can add 1–2 days to processing time.
- Can I return it if it doesn't function?
- Ironclad Armory accepts returns within 30 days for manufacturing defects but does not accept returns for buyer’s remorse or regulatory issues. All returns must go through an authorized FFL and include original packaging. Expect a 10–14 day turnaround for inspection and replacement.